Based on work carried out by the DOEs Lawrence Berkeley National Laboratory, it has been found that homes in California, which have photovoltaic systems installed on them have sold for a premium. Expressed in dollars per watt of installed photovoltaics, this premium amounts to between $3.90 and $6.40 per watt.
This, says the Berkeley Lab researchers, corresponds to an average sale price of around $17,000 for a "relatively new" 3,100 watt photovoltaic system, the average size of PV systems in the Berkeley Lab dataset.
It is also said to compare to the average investment – approximately $5 per watt over the 2001 to 2009 period – which homeowners have made to install their photovoltaic systems.
"We find compelling evidence that solar PV systems in California have boosted home sales prices," states Ben Hoen, lead researcher on the study and a Principal Research Associate at Berkeley Lab.
"These average sales price premiums appear to be comparable with the average investment that homeowners have made to install PV systems in California, and of course homeowners also benefit from energy bill savings after PV system installation and prior to home sale."
However, there seems to be a correlation between the age of the photovoltaic system and the premium. In a statement released, the researchers say: "The research also shows that, as PV systems age, the premium enjoyed at the time of home sale decreases. Additionally, existing homes with PV systems are found to have commanded a larger sales price premium than new homes with similarly sized PV systems."
Co-author and Berkeley Lab Principle Scientific Engineering Associate Peter Cappers elaborates: "One reason for the disparity between existing and new homes with PV might be that new home builders also gain value from PV as a market differentiator that speeds the home sales process, a factor not analyzed in the Berkeley Lab study. More research is warranted to better understand these and related impacts."
The research analyzed a dataset of more than 72,000 California homes that sold from 2000 through mid-2009, approximately 2,000 of which had a photovoltaic system at the time of sale.